Once the capital of the ghibrani nation-state of Kolleo, Arkeost is the only remaining functional ghibrani city on the planet. A pinkish dome of force surrounds the city out to a half-mile outside the city limits. Though the membrane ghibranis who live in the city can open temporary portals in the dome, they rarely explore the surrounding wastelands, as Arkeost supplies them with everything they need.

Arkeost is ruled by a council of membrane ghibranis known as the Most Elevated, though their decisions are mostly ceremonial, as the day-to-day operations of the city are carried out by servitor robots controlled by a central mainframe programmed before the war. However, as the automated repair drones run low on materials, the gleaming towers are beginning to fall into disrepair.